The present invention relates generally to methods for producing golf club heads and, more particularly, to an improved non-mechanical method for producing a golf club head.
Modern golf clubs have typically been classified as woods, irons or putters. Additionally, a newer class of golf clubs termed “utility” clubs or “iron woods,” seek to replace low-lofted long irons or higher numbered fairway woods. The term “wood” is a historical term that is still commonly used, even for golf clubs that are constructed of steel, titanium, fiberglass and other more exotic materials, to name a few. The woods are now often referred to as “metal woods.” The term “iron” is also a historical term that is still commonly used, even though those clubs are not typically constructed of iron, but are rather constructed of many of the same materials used to construct “woods.”
One particular improvement that relates especially to metal woods is the use of lighter and stronger metals, such as titanium. A significant number of the premium metal woods, especially drivers, are now constructed primarily using titanium. The use of titanium and other lightweight, strong metals has made it possible to create metal woods of ever-increasing sizes. The size of metal woods, especially drivers, is often referred to in terms of volume. For instance, current drivers may have a volume of 300 cubic centimeters (cc) or more. Oversized metal woods generally provide a larger sweet spot and a higher inertia, which provides greater forgiveness than a golf club having a conventional head size.
One advantage derived from the use of lighter and stronger metals is the ability to make thinner walls, including the striking face and all other walls of the metal wood club. This allows designers more leeway in the positioning of weights. For instance, to promote forgiveness, designers may move the weight to the periphery of the metal wood head and backwards from the face. As mentioned above, such weighting generally results in a higher inertia, which results in less twisting due to off-center hits. One disadvantage derived from the use of stronger materials is the increased difficulty of mechanically manipulating and machining them.
There are limitations on how large a golf club head can be manufactured, which is a function of several parameters, including the material, the weight of the club head, the strength of the club head, and the materials used. Additionally, to avoid increasing weight, as the head becomes larger, the thickness of the walls must be made thinner, including that of the striking face. As a result, as the striking face becomes thinner, it has a tendency to deflect more and more at impact, and thereby has the potential to impart more energy to the ball. This phenomenon is generally referred to as the “trampoline effect.” A properly constructed club having a thin face can therefore impart a higher initial velocity to a golf ball than can a club having a rigid thick face. Because initial velocity is an important factor in determining how far a golf ball travels, this is very important to golfers.
It is appreciated by those skilled in the art that the initial velocity imparted to a golf ball by a thin-faced metal wood varies depending on the location of the point of impact of a golf ball on the striking face. Generally, balls struck in the sweet spot will have a higher rebound velocity. Many factors contribute to the location of the sweet spot, including the location of the center of gravity (CG) and the shape and thickness of the striking face.
Prior golf club heads have provided an increased initial or launch velocity of a golf ball, by incorporating a lightweight, flexible face. Manufacturers of metal wood golf club heads have more recently attempted to manipulate the performance of their club heads by designing what is generically termed a variable face thickness profile for the striking face, and in particular, with the use of lightweight materials, such as titanium alloys. Golf club heads with striking faces that incorporate a complex design (e.g., a variable thickness profile) and golf club heads that are made out of a very strong materials (e.g., titanium alloys) are very difficult to manufacture using mechanical methods. Typically, mechanical methods of machining cannot produce golf club heads incorporating complex shapes and designs. Attempts to create golf club heads with complex shapes and designs using mechanical methods typically result in the golf club heads having poor quality. Additionally, the stronger base materials make it even more difficult and time consuming to mechanically manipulate the materials into a superior quality golf club head.
Numerous golf club heads with complex or irregular surfaces have been designed and created. By way of example only, some of them include using ribs formed on the back of a club face, one or more thin rings, a power bar and a cone formation. Multiple thin rings have been attached by various means so as to add mass directly behind the sweet spot, and alternatively a spiral formation has been used, wherein the multiple rings or spiral mass extend from the sweet spot substantially toward the periphery of the face plate. A single thin ring at the sweet spot has been used on an iron club head in conjunction with an added toe mass in order to reposition a point of least rigidity to the center of the face.
Generally, as time goes on, golf club heads incorporate surfaces with increasingly complex and irregular shapes. Additionally, golf club heads tend to be manufactured from stronger and stronger materials. Strong base materials and complex and irregular surfaces are used to provide certain desired advantages to the golfer (e.g., larger sweet spot, increased coefficient of restitution). To provide golfers with these desired advantages, frequently, the surfaces of these new golf club heads must be made with extreme precision and to exacting standards.
Unfortunately, conventional mechanical methods (e.g., milling or forging) of producing golf club heads have many economic and technical drawbacks. As mentioned above, there is a general trend toward using stronger and stronger base materials in golf club heads. Because of their strength, these base materials are more difficult to machine using traditional mechanical methods. They require more time to manipulate into the proper form and wear down the components of a mechanical machining process in less time, requiring additional re-tooling. Therefore, additional costs are incurred and delays are experienced when stronger materials are mechanically machined. Mechanical methods of machining strong materials can also create extreme temperatures and residual stresses that have an undesirable effect on these materials. Additionally, materials that are highly flexible or slender are difficult to cut or clamp and are therefore difficult to machine using mechanical methods.
Another drawback to using mechanical methods to produce golf club heads is the difficulty of producing complex or irregular surfaces having superior quality. Generally, the mechanical machining methods used today cannot form golf club heads having highly complex or irregular surfaces with superior quality. This is especially true when the golf club head is made of a very strong material.
The foregoing discussion demonstrates that there exists the need for a more accurate, efficient and cost-effective method for producing golf club heads that produces superior quality regardless of the materials used or complexity of the design.